If your car is struggling to start but running fine, it’s most likely a problem with your car’s battery or alternator—so it’s important to identify the exact problem quickly. If you’re sure the battery and alternator are fine, this could indicate other engine troubles.
We’ve all been there: you’re getting in your car, you turn the key… and nothing. Maybe you try again, and it sputters to life. Or maybe it takes a few frantic switches back and forth before your car decides to start. But then it’s running fine, so you drive off and forget about it—until next time.
If your car is struggling to start but running fine, this most commonly indicates an issue with your car’s battery or alternator. But how do you identify what’s wrong in the first place?
Car battery
Your car battery lives under your vehicle’s hood and is the primary source of power for your car’s electrical components. The battery helps power your vehicle’s lights, including the lights on your dashboard, as well as your radio, power windows, and other essential functions.
It also sends voltage to your car’s starter—which is why if your car is struggling to start, you’ll want to attend to the battery first.
If you think a faulty battery is to blame for your car troubles, you’ll want to look out for the following:
Rapid clicking
If you’re turning your key and getting a rapid clicking noise in response, it could mean your car battery lacks the power to turn over the engine. You’ll want to check the output voltage levels (which can easily be done with a voltmeter).
If the output reading is under 12, you’ll need a mechanic to take a second look.
Battery power drain
Clicking could also indicate your battery is experiencing a power drain. Battery drains occur when excessive amounts of power are discharged after shutting off your car’s engine (such as vehicle lights not shutting off properly).
Fixing a parasitic power drain involves replacing your battery’s cables, which requires at least a little prior experience with DIY car fixes.
Battery corrosion
The clicking sound may also be a sign of a corroded battery terminal. To check for corrosion, you’ll want to inspect your battery for green or blue-deposit buildups (it’ll probably look grimy) that could be interfering with the transfer of power from your battery to other components of your engine.
Loose battery cables
Loose battery cables or frayed wires can also prevent or interfere with your car starting, and may be accompanied by a clicking noise. If this is the problem, you’ll want to replace the battery cables.
Low electrolyte levels
Battery electrolyte is the liquid substance used to power your battery—it’s like car battery acid. If electrolyte levels are low, the battery won’t function well and will need to be recharged.
In some cases, you may have to replace the battery—a quick fix at most garages.
Swollen battery case
Fluctuating weather conditions can cause your battery case to swell and warp, reducing your battery’s output voltage. Once your battery is swollen, it won’t work properly—you’ll have to replace it.
Sulfuric smell
If you’re getting whiffs of sulfur in your car, it could be an indication that your battery is leaking fluid. Fluid leaks can damage other components in your car’s engine, impacting your car’s ability to start, so it’s necessary to replace the battery promptly to correct the problem.
Dead or dying battery
Sometimes, car batteries just run out of juice. An easy way to tell if your battery’s time is up is if your key fob stops working. Jump-starting your vehicle is an easy (albeit temporary) solution to a dying car battery. Eventually, you’ll want to get it replaced.
Car alternator
Your car’s alternator is connected to the engine and helps maintain your battery’s charge. A damaged alternator can run bills upward of $1,000 or more if not addressed, and can also harm your car’s battery, too.
Common symptoms of a faulty car alternator include:
Loud noises
Loud rumbling or grinding noises are an indicator of a faulty alternator. Specifically, your alternator’s belt or pulley system may be on the fritz. You’ll have to replace these components to fix the problem, but if noises persist, it means you’ll need a new alternator entirely to get your car back to running smoothly.
Engine cranking
If it sounds like your engine is cranking too slowly, it could be the fault of your alternator.
Flickering lights
If it seems your headlights are flickering, or that they’re not as bright when you’re idling, your alternator is likely to blame. The lights on your dashboard may also dim at this time; to address the problem, you’ll want to check your alternator’s drive belt. It could also be an issue with a corroded battery terminal or loose battery cables.
Voltage leaks
As with your battery, your alternator can also leak. Lower voltage levels make it harder for your car to start running. To check your alternator’s voltage levels, you can use a voltmeter.
Battery light
If your car’s dashboard battery light comes on (and stays on) after starting your car, it means there’s trouble with the alternator. You’ll know it’s the battery light because it’s shaped just like a car battery!
Stuck or failed ignition switch
The ignition switch is the part of your electrical switch that turns the engine over. If it’s stuck, damaged, or failing, you’ll notice that any electrically-powered car accessories won’t turn on. If it’s the ignition switch at fault, you’ll need a mechanic’s help to resolve the issue.
Other common problems
So you’ve inspected your battery and alternator, and everything checks out. But your car is still struggling to start. What else could be the problem?
- Starter: Clicking noises can also indicate problems directly with your car’s starter. If the electrically-powered components of your car (like the power windows, radio, etc.) are still working fine, but the car isn’t starting or struggling to start, it’s your starter that’s the problem.
- Clogged fuel filter: Your car’s fuel filter helps keep the gas you power your vehicle with clean and easily flowing. On occasion, the filter will get clogged with excess debris (dirt, particles, rust) from your fuel and will need replacing.
- Broken fuel pump/frozen fuel lines: A broken fuel pump or frozen lines can prevent fuel from circulating through your engine and starting your car. Luckily, replacing a fuel pump is cheap, and you can easily thaw fuel lines with a little bit of additive.
- Oil is too thick/dirty: If you’re way overdue on an oil change, thick or dirty oil could be the culprit! Try changing the oil and replacing the filter to correct the issue.
- Spark plugs need replacing: Spark plugs play an important role in sparking the fuel and getting your engine running. Every 100,000 or so, they’ll need replacing.
FAQ
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Why does my car sound like it’s struggling to start?
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What to do if your car is hard to start?
Melanie Reiff is an expert insurance writer and editor with over half a decade of experience in professional writing. Guided by a lifelong love of storytelling, it’s Melanie’s mission to help people problemsolve by means of creative and engaging content. Melanie specializes in analyzing the ways in which society, technology, and culture intersect, previously working with clients in travel, technology, and social impact to tell their stories.
As an editorial team lead at Jerry, Melanie has translated her prior experience into creating and editing insurance content that can help drivers and homeowners find the solutions they need and make informed moves.
Prior to joining Jerry’s editorial team, Melanie worked as a freelance content marketing strategist and was the full-time director of choir at Rampart High School Acadamy in Colorado Springs.
